Pneumatic vehicle tire having a reinforcing layer with steel monofilaments

Abstract

The invention relates to a pneumatic vehicle tire with a reinforcing layer which has steel monofilaments with a cross-sectional surface area of 98 mm² to 125 mm² per meter of the reinforcing layer, said steel having a carbon content of at least 0.86 wt.%. The aim of the invention is to provide an improved durability while maintaining an advantageous rolling resistance. This is achieved in that the monofilaments have a brass coating with a copper content of 61 wt.% to 70 wt.% and a zinc content of 30 wt.% to 39 wt.%, the monofilaments have a linear density of 92 g / 100 m to 105 g / 100 m, each of the monofilaments has a tensile density Td of 34 MPa / (g / 100m) to 39 MPa / (g / 100m), the tensile density Td is defined as a quotient of the tensile strength and linear densities of each reinforcing layer, the reinforcing layer has a surface strength AS of 109 Nmm² to 166 Nmm², said surface strength AS being provided as a product of the fracture force and the diameter of a monofilament and the distance between the monofilament and an adjacent monofilament of the reinforcing layer, and the rubber material has an elongation at break of 300% to 450%.

Description

[0001] Description

[0002] Pneumatic vehicle tire having a reinforcement layer with steel monofilaments

[0003] The invention relates to a pneumatic vehicle tire, in particular of radial design, with a reinforcement layer comprising reinforcements made of steel, which are arranged within the reinforcement layer essentially parallel and spaced from one another and embedded in a rubber material, wherein each of the reinforcements is designed as a monofilament, wherein the monofilaments have a cross-sectional area of ​​98 mm 2 up to 125 mm 2 per meter of reinforcement layer and wherein the steel has a carbon content of at least 0.86 wt.%.

[0004] A pneumatic vehicle tire generally comprises an air-impermeable inner layer, a carcass comprising at least one carcass reinforcement layer, the carcass extending from the crown region of the tire across the sidewalls to the bead region and anchored there by wrapping tensile bead cores, a radially outer profiled tread, and a belt comprising belt reinforcement layers arranged between the tread and the carcass, which belt may be covered radially outwardly with a belt bandage. The belt bandage may be single- or multi-layered and covers at least the belt edges.

[0005] To produce a reinforcement layer, particularly the belt or carcass, reinforcements are usually embedded in rubber material. This is done by passing a series of essentially parallel reinforcements lengthwise through a calender or extruder to be coated with the rubber material. These webs are usually cut transversely to their lengthwise direction so that the pieces can be used individually or joined together as reinforcement layers in the tire. The belt usually has at least two belt reinforcement layers that are arranged at an angle to each other. The belt ensures the rigidity of the tread in the longitudinal and transverse directions. This serves to transmit power while driving, improves lateral grip, and reduces tire wear.

[0006] The carcass has at least one carcass reinforcement layer, wherein in a pneumatic vehicle tire of radial design the reinforcements of the at least one carcass layer are arranged in the sidewalls at an angle of 0° to 10°, preferably of 0° to 8°, to the radial direction.

[0007] It is well known and common practice to use steel cords as belt reinforcements. Belt reinforcement layers used in pneumatic car tires often feature steel cords made of multiple high-tensile steel filaments, e.g., 2x, 3x, 2+1, etc. A disadvantage of belt reinforcement layers made with the aforementioned steel cords is that they are comparatively thick and heavy, which adversely affects rolling resistance.

[0008] To achieve thinner, rolling-resistance-optimized reinforcement layers, it is also known to use thin steel monofilaments with a high reinforcement density. For example, DE 10 2016 225231 A1 discloses a belt reinforcement layer comprising ultra-tensile steel monofilaments with a small diameter of 0.35 mm, which are arranged in the reinforcement layer with a high thread density of 90 to 130 epdm to compensate for the small diameter.

[0009] However, the increased thread density, which compensates for the lower strength of the thin monofilaments compared to cords made of multiple steel filaments, leads to various challenges, which, for example, affect the service life of the tire due to the higher number of reinforcements and the narrower reinforcement spacing. The high thread density can result in increased crack formation and crack propagation. The deformation properties of the reinforcement layer, and thus especially the handling characteristics of the tire, are also influenced by the design of the reinforcements.

[0010] It was the primary object of the present invention to eliminate or at least reduce the disadvantages of the prior art described above.

[0011] The task is therefore to develop a pneumatic vehicle tire that offers improved durability while still offering advantageous rolling resistance.

[0012] This is achieved by the monofilaments having a brass coating with a copper content of 61 wt% to 70 wt% and a zinc content of 30 wt% to 39 wt%, the monofilaments each having a linear density of 92 g / 100 m to 105 g / 100 m, the monofilaments each having a tensile density Td of 34 MPa / (g / 100m) to 39 MPa / (g / 100m), the reinforcement layer having a surface strength AS of 109 Nmm 2 up to 166 Nmm 2and that the rubber material has an elongation at break of 300% to 450%. The areal strength AS of a reinforcement layer is given as the product of a breaking force and a diameter of a reinforcement of the reinforcement layer, as well as a distance between the reinforcement and an adjacent reinforcement of the reinforcement layer. The distance plus the diameter is thus the repeat spacing of the reinforcements. The breaking force of the reinforcement is measured according to ASTM D 2969.

[0013] The cross-sectional area of ​​a monofilament runs perpendicular to the direction of its extension. The tensile density Td of a reinforcement member is defined as the quotient of the tensile strength and the linear density of the respective reinforcement member. The tensile strength is measured according to ASTM D 2969.

[0014] The elongation at break of the rubber material is measured at room temperature according to DIN 53504. The high carbon content of the steel monofilaments, at least 0.86 wt.%, enables the monofilaments to have an advantageously high tensile strength. The design of the reinforcements as monofilaments allows for particularly good penetration by the rubber material, thereby preventing the corrosion propagation promoted by the high carbon content. At the same time, the design of the reinforcements as monofilaments allows for a thin reinforcement layer and thus continued low rolling resistance. The brass coating of the monofilaments, with a copper content of 61 wt.% to 70 wt.% and a zinc content of 30 wt.% to 39 wt.%, promotes optimal adhesion between the steel and the rubber material. This results in improved tire durability while maintaining low rolling resistance.

[0015] The comparatively high linear density of the monofilaments, measured in g per 100 m of the respective monofilament, from 92 g / 100 m to 105 g / 100 m, leads to improved compression properties and thus, when used as a belt layer, improved handling characteristics. At the same time, this high linear density, combined with the low tensile density Td of 34 MPa / (g / 100 m) to 39 MPa / (g / 100 m), ensures reduced fatigue strength and thus greater durability.

[0016] It has been shown that the interaction between the reinforcement and the rubber material surrounding the reinforcement, particularly the amount of rubber material surrounding it and its elongation at break, is of particular importance for tire properties. The tensile strength takes into account and combines the breaking force with the diameter of the monofilaments and the distance to an adjacent monofilament. It has been shown that a tensile strength AS of 109 Nmm 2 up to 166 Nmm 2 In conjunction with the high linear density and the elongation at break of the rubber material of 300% to 450%, particularly that arranged between the reinforcements, this layer enables an excellent compromise between service life, handling characteristics, and tire robustness. Such a reinforcement layer exhibits improved properties with regard to crack formation and crack propagation.

[0017] This provides a pneumatic vehicle tire that, thanks to the arrangement and weight distribution of steel to rubber material in the reinforcement layer and the material properties of the rubber material, continues to offer advantageous rolling resistance while maintaining improved durability. These advantages are particularly evident in a vehicle tire that incorporates the reinforcement layer as a belt layer. Such a pneumatic vehicle tire exhibits advantageous handling characteristics.

[0018] Compared to a reinforcement layer with reinforcements of a conventional 2x high-tensile construction, a pneumatic vehicle tire is possible that has improvements in rolling resistance, handling and plunger while continuing to provide advantageous tire life and robustness.

[0019] An advantageous embodiment is provided in that the monofilaments have a compression modulus of 138 GPa to 155 GPa and / or a compression displacement of 0.95% to 1.05% and / or a compression stress of 1400 MPa to 1500 MPa.

[0020] It has been shown that this combination of steel monofilaments and rubber material in the reinforcement layer, together with a compression modulus of 138 GPa to 155 GPa and / or a compression strain of 0.95% to 1.05% and / or a compression stress of 1400 MPa to 1500 MPa, enables high compression force up to the point of buckling of the monofilaments. This results in further improved deformation properties of the reinforcement layer. When used as a belt layer, this results in a pneumatic vehicle tire with further improved handling properties. It is advantageous if the monofilaments have a compression modulus of 138 GPa to 155 GPa and a compression strain of 0.95% to 1.05% and a compression stress of 1400 MPa to 1500 MPa.

[0021] The determination of the compression modulus, compression strain, and compression stress of a steel strength member, in particular a monofilament, is known to the expert. To determine the respective characteristic of the monofilament, a sample from a rubber cylinder, in particular a rubber cylinder made of the same rubber material as the rubber material of the strength member layer, with the monofilament arranged along the rotational axis of the cylinder, is usually tested in comparison with a sample from a corresponding rubber cylinder that is free of such a monofilament. The respective cylinder can have a diameter of 15 mm and a length of 25 mm, and the test can be carried out at room temperature with a preload of 2 N and a test speed of 5 mm / min.To determine the compression properties of the monofilament, the difference between the two samples with and without monofilament must be taken into account.

[0022] An advantageous embodiment is provided by the fact that the monofilaments each have an out-of-plane bending stiffness of 270 Nmm 2 up to 340 Nmm 2 have.

[0023] It has been shown that the inventive combination of steel monofilaments and rubber material in the reinforcement layer together with the high flexural rigidity outside the plane of the monofilaments of 270 Nmm 2 up to 340 Nmm 2 This results in a pneumatic vehicle tire optimized with regard to the deformation properties of the reinforcement layer. When used as a belt layer, this results in a pneumatic vehicle tire that is further optimized with regard to handling characteristics.

[0024] The flexural rigidity of a steel reinforcement member, especially a monofilament, can be determined using the 3-point bending test familiar to the expert. The flexural rigidity of the monofilament is determined as the result of a force acting on the reinforcement member perpendicular to the direction of extension of the monofilament. A straight piece of monofilament is tested, with the test length and the distance between two contact points on which the monofilament rests depending on the linear density of the monofilament.

[0025] An advantageous embodiment is provided in that the monofilaments each have a tensile strength of 3500 MPa to 3700 MPa, preferably that a force of 285 N to 325 N is applied for an elongation of 1%.

[0026] Monofilaments with this tensile strength exhibit an advantageously high breaking force. The tensile strength and the force at 1% elongation are measured according to ASTM D 2969.

[0027] An advantageous embodiment is provided in that the strength member layer has a weight fraction of steel of 47 wt.% to 63.5 wt.%, preferably of 48.9 wt.% to 62.3 wt.%, particularly preferably of 52 wt.% to 58 wt.% and in that the strength member layer has a spacing factor S of 2.00 to 2.67, preferably of 2.05 to 2.57, particularly preferably of 2.10 to 2.50.

[0028] The spacing factor S is given in the context of the invention as: S=1 + ((y+y'+x) / (2xd)), where y is a thickness of the reinforcement layer on a first side of a monofilament of the reinforcement layer, y' is a thickness of the reinforcement layer on an opposite second side of the monofilament, in each case measured perpendicular to a planar extension of the reinforcement layer, x is the distance between the monofilament and an adjacent monofilament of the reinforcement layer and d is the diameter of the monofilament, y and y' are measures for the rubber coating thickness of the reinforcement layer above and below the cord, where y+y'+d is the total thickness of the reinforcement layer, measured perpendicular to the planar extension of the reinforcement layer. Furthermore, d+x gives the repeat spacing (pitch) of the monofilaments.

[0029] The spacing factor S takes into account the coating of the monofilaments with the rubber material of the reinforcement layer. The spacing factor S characterizes the reinforcement layer, particularly with regard to the probability of crack propagation and the absorption of shear forces.

[0030] The high linear density of the monofilaments from 92 g / 100 m to 105 g / 100 m together with the high cross-sectional area of ​​the monofilaments of 98 mm 2 up to 125 mm 2per meter of reinforcement layer, in conjunction with the comparatively moderate weight proportion of the reinforcement layer of steel of 47 wt.% to 63.5 wt.%, preferably of 48.9 wt.% to 62.3 wt.%, particularly preferably of 52 wt.% to 58 wt.%, enable a reinforcement layer which, with regard to layer thickness and layer weight, is also advantageous with regard to rolling resistance and is particularly suitable as a belt layer.In conjunction with the spacing factor S of 2.00 to 2.67, preferably of 2.05 to 2.57, particularly preferably of 2.10 to 2.50, which further characterizes the coating of the monofilaments with the rubber material and enables advantageous absorption of shear forces by the coating rubber material, as well as the elongation at break of 300% to 450% of the coating rubber material, the reinforcement layer designed in this way also has reduced crack formation and crack propagation, whereby the durability of the reinforcement layer is further improved.

[0031] An advantageous embodiment is provided in that the monofilaments are free of twist around their axis.

[0032] This enables a stable coating process of the reinforcements with the rubber material. At the same time, the orientation and uniform distribution of the monofilaments within the reinforcement layer is facilitated. Preferably, the reinforcement layer has the same amount of rubber material above and below the reinforcements. An advantageous embodiment is achieved by the monofilaments having a twist angle of a maximum of 10°, preferably a maximum of 1°.

[0033] Such a small twist angle of a maximum of 10° has only a minor impact on the properties of the monofilament. Such a small twist enables a stable coating process of the reinforcements with the rubber material. A twist angle of a maximum of 1° is particularly advantageous. At the same time, the orientation and even distribution of the monofilaments within the reinforcement layer is facilitated.

[0034] The twist angle is calculated as atan(irxd / P )×180 / TT, where d denotes the diameter of the monofilament and P the pitch of the twist. The monofilament can be examined using a light microscope. The diameter d (in millimeters) and a value corresponding to half the twist pitch P (in millimeters) can be determined. The value is determined using a draw mark on the surface of the monofilament. The value is multiplied by 2 to obtain the twist pitch P.

[0035] Preferably, the reinforcement layer above and below the reinforcement has the same amount of rubber material.

[0036] An advantageous embodiment is provided in that the rubber material has a tensile strength of 15 N / mm 2 up to 22 N / mm 2 has.

[0037] The tensile strength of the rubber material is measured at room temperature according to DIN 53504. Such a tensile strength enables an advantageous compromise between service life and rolling resistance properties of the reinforcement layer, in particular the belt layer, of the tire.

[0038] An advantageous embodiment is provided by the rubber material having a Shore hardness of 77 to 81 (Shore A). The Shore hardness of the rubber material is measured at room temperature according to DIN 53505. Such a Shore hardness enables a favorable compromise between service life and rolling resistance properties of the tire's reinforcement layer, in particular the belt layer.

[0039] An advantageous embodiment is provided in that the rubber material has a rebound resilience of 38 to 45.

[0040] The rebound resilience of the rubber material is measured at room temperature according to DIN 53512. Such rebound resilience enables an advantageous compromise between service life and rolling resistance properties of the reinforcement layer, in particular the belt layer, of the tire.

[0041] An advantageous embodiment is provided in that the pneumatic vehicle tire has a belt and that the reinforcement layer is a reinforcement layer of the belt, preferably that the belt has two such reinforcement layers, the reinforcements of which cross at an angle of 18° to 45°.

[0042] A pneumatic vehicle tire comprising such a belt with at least one reinforcement layer according to the invention as the belt reinforcement layer exhibits advantageous durability and handling properties with good rolling resistance. It is, in particular, a tire of radial design.

[0043] The vehicle tire comprising the belt designed according to the invention is preferably a tire for a passenger car, a light truck, or a commercial vehicle. It is preferably a passenger car or a light truck. An advantageous embodiment is provided in that the pneumatic vehicle tire, in particular of radial design, has a carcass and in that the reinforcement layer is a reinforcement layer of the carcass.

[0044] A pneumatic vehicle tire, in particular of a radial design, comprising a carcass with at least one reinforcement layer according to the invention as a carcass reinforcement layer, exhibits advantageous durability properties with good rolling resistance. If the pneumatic vehicle tire is of a radial design, the reinforcements of the carcass reinforcement layer are arranged in the sidewalls at an angle of 0° to 10°, preferably 0° to 8°, to the radial direction.

[0045] The vehicle tire, in particular of radial design, comprising the carcass designed according to the invention is preferably a tire for a passenger car, a light truck, a commercial vehicle, or the like. It is preferably a pneumatic vehicle tire for a passenger car. Motor vehicles driven by an electric motor, in particular such passenger cars, comprising one or more tires according to the invention particularly benefit from low rolling resistance combined with improved handling characteristics and improved durability.

[0046] All embodiments of the pneumatic vehicle tire according to the invention presented in this description represent examples of the embodiment of the invention and are not to be viewed as limiting. Accordingly, individual or multiple features of an embodiment alone, or the combination of features of various embodiments, provide further embodiments of the invention, which are the subject matter of the invention, unless explicitly explained otherwise in the description. Furthermore, combinations of preferred and particularly preferred embodiments can also be combined with one another. An exemplary embodiment of a pneumatic vehicle tire according to the invention is given below.It is a pneumatic vehicle tire of radial design with a reinforcement layer comprising reinforcements made of steel, which are arranged substantially parallel and spaced from one another within the reinforcement layer and are embedded in a rubber material, wherein each of the reinforcements is designed as a monofilament, wherein the monofilaments have a cross-sectional area of ​​98 mm. 2 up to 125 mm 2 per meter of reinforcement layer and wherein the steel has a carbon content of at least 0.86 wt.%.

[0047] The tire is characterized in that the monofilaments have a brass coating with a copper content of 61 wt.% to 70 wt.% and a zinc content of 30 wt.% to 39 wt.%, that the monofilaments each have a linear density of 92 g / 100 m to 105 g / 100 m, that the monofilaments each have a tensile density Td of 34 MPa / (g / 100m) to 39 MPa / (g / 100m), where the tensile density Td is defined as the quotient of tensile strength and linear density of the reinforcement layer, that the reinforcement layer has an areal strength AS of 109 Nmm 2 up to 166 Nmm 2 wherein the areal strength AS is given as the product of a breaking force and a diameter of a monofilament of the reinforcement layer and a distance between the monofilament and an adjacent monofilament of the reinforcement layer, and that the rubber material has an elongation at break of 300% to 450%.

[0048] The monofilaments can have a compression modulus of 138 GPa to 155 GPa, a compression strain of 0.95% to 1.05%, and / or a compression stress of 1400 MPa to 1500 MPa. The monofilaments can have an out-of-plane bending stiffness of 270 Nmm each. 2 up to 340 Nmm 2 The monofilaments can each have a tensile strength of 3500 MPa to 3700 MPa, preferably a force of 285 N to 325 N is required for an elongation of 1%. The strength member layer can have a weight fraction of steel of 47 wt.% to 63.5 wt.%, preferably of 48.9 wt.% to 62.3 wt.%, particularly preferably of 52 wt.% to 58 wt.%, wherein the strength member layer has a spacing factor S of 2.00 to 2.67, preferably of 2.05 to 2.57, particularly preferably of 2.10 to 2.50.

[0049] The monofilaments may have a twist angle of up to 10°, preferably up to 1°. The monofilaments may be free of twist around their own axis.

[0050] The rubber material of the reinforcement layer can have a tensile strength of 15 N / mm 2 up to 22 N / mm 2 The rubber material of the reinforcement layer can have a Shore hardness of 77 to 81 (Shore A). The rubber material of the reinforcement layer can have a rebound resilience of 38 to 45.

[0051] Such a pneumatic vehicle tire is particularly advantageous when the reinforcement layer is a belt ply. It is even more advantageous when both belt plies, which intersect at an angle of 18° to 45°, are designed in this way. However, a reinforcement layer as described above can also be a carcass ply of a pneumatic vehicle tire.

[0052] Tire tests were conducted to determine the durability of tires. These are pneumatic radial tires, size 175 / 65 R15, each with two belt plies. The belt plies are designed as reinforcement layers, each comprising steel reinforcements arranged essentially parallel and spaced apart within each reinforcement layer and embedded in a rubber material. The reinforcements of the two belt plies of the respective tire intersect at an angle of 18° to 45°.

[0053] Comparison tyres not according to the invention (reference tyre 1,

[0054] Reference tires 1 and 2 (reference tires 2) and tires according to the invention (example tires) were tested. Reference tires 1, reference tires 2, and the example tires differ only in the design of their belt layers.

[0055] Table 1 shows the parameters of a belt ply or a strength member (FT) of the belt ply of a reference tire 1, reference tire 2 and an example tire according to the invention.

[0056] Table 2 provides a comparative evaluation of the properties of the tested tires.

[0057] The belt ply of an example tire according to the invention listed in Table 1 comprises monofilaments as reinforcements, with the steel having a carbon content of at least 0.86 wt.%. The monofilaments have a maximum twist angle of 1°. In particular, they are free of twist around their axis. The reinforcement ply has, in particular, a steel weight fraction of 57.8% and a spacing factor S of 2.19.

[0058] The belt ply of a reference tire 1 listed in Table 1 uses standard steel cords of construction x2 with a lay length of 14 mm as reinforcement. The steel has a carbon content of less than 0.86 wt.%.

[0059] The belt ply of a reference tire 2 listed in Table 1 features steel monofilaments as reinforcement with a lower linear density than the monofilaments of the example ply, with the steel also having a carbon content of at least 0.86 wt.%. The monofilaments have a maximum twist angle of 1°. In particular, they are free of any twist around their axis.

[0060] The strength members of the belt plies of the test tires each have a brass coating with a copper content of 61% to 70% and a zinc content of 30% to 39%. The rubber material of the belt plies each has an elongation at break of 300% to 450%. The tensile strength and the force at 1% elongation, as well as the breaking force of each strength member, are measured according to ASTM D 2969.

[0061] The elongation at break of the rubber material is measured at room temperature according to DIN 53504. The tensile strength of the rubber material is measured at room temperature according to DIN 53504. The Shore hardness of the rubber material is measured at room temperature according to DIN 53505. The rebound resilience of the rubber material is measured at room temperature according to DIN 53512.

[0062] To determine the compression modulus, compression strain, and compressive stress, a sample from a rubber cylinder, specifically a rubber cylinder made of the same rubber material as the rubber material of the reinforcement layer, with the steel reinforcement arranged along the cylinder's rotation axis, was tested in comparison with a sample from a corresponding rubber cylinder that was free of such a reinforcement. The respective cylinder had a diameter of 15 mm and a length of 25 mm, and the test was conducted at room temperature with a preload of 2 N and a test speed of 5 mm / min. To determine the compression properties of the reinforcement, the difference between the two samples with and without the reinforcement was taken into account.

[0063] The out-of-plane bending stiffness of each strength member is measured using a standard 3-point bending test. The bending stiffness of the steel strength member is determined as the result of a force acting perpendicular to the strength member's extension direction. A straight piece of steel strength member is tested, with the test length and the distance between two contact points on which the strength member rests depending on the linear density of the strength member. The bending stiffness of the monofilament in the example was measured with a test length of 50.02 mm, a distance between the two contact points of 20.02 mm, a speed of 2.503 mm / s, and a preload of 0.03 N.

[0064] The twist angle is calculated as atan(irxd / P )×180 / TT, where d is the diameter of the monofilament and P is the pitch of the twist. The monofilament is examined using a light microscope. The diameter d (in millimeters) and a value corresponding to half the twist pitch P (in millimeters) are determined. This value is determined using a draw mark on the surface of the monofilament. The value is multiplied by 2 to obtain the twist pitch P.

[0065] Table 1

[0066] Table 2 provides a comparative evaluation of the properties of the tested tires.

[0067] Table 2

[0068] The determined tire durability of reference tire 1 is rated as 100%. It is evident that reference tires 2 have a lower tire durability than reference tires 1. The example tires according to the invention, on the other hand, have a tire durability comparable to reference tires 1. It is important to note that the tire durability is improved compared to reference tires 2, which, like the example tires according to the invention, have steel monofilaments as reinforcement. This is made possible by the lower tensile density Td compared to reference tires 2 and the higher areal strength AS, together with the increased linear density and the continued high elongation at break of the rubber material of the example tires according to the invention.

[0069] At the same time, the linear density of the monofilaments as well as the cross-sectional area per meter of the reinforcement layer of the example tires and the reference tires 2 are significantly reduced compared to the reference tires 1, thus enabling a further advantageously reduced rolling resistance compared to the reference tires 1. As shown in Table 2, the determination of the handling properties of the test tires revealed an advantage of the example tires according to the invention, especially over the reference tires 2. Here, too, the increased linear density proved to be advantageous.

[0070] The increased values ​​of the compression modulus, compression strain, and compression stress, as well as the significantly increased out-of-plane flexural stiffness, have also proven advantageous for the further advantageous rolling resistance, greater robustness, and improved handling characteristics of the example tires according to the invention compared to Reference Tire 2. The increased force at 1% elongation with only a slight decrease in tensile strength have also proven advantageous.

Claims

Patent claims 1. Vehicle pneumatic tires, in particular of radial design, comprising a reinforcing layer comprising reinforcing steel reinforcing elements which are arranged substantially parallel and spaced apart from each other within the reinforcing layer and are embedded in a rubber material, wherein each of the reinforcing elements is designed as a monofilament, wherein the monofilaments have a cross-sectional area of ​​98 mm² 2 up to 125 mm 2 per meter of load-bearing layer and wherein the steel has a carbon content of at least 0.86 wt.%, characterized in that • the monofilaments have a brass coating with a copper content of 61 wt.% to 70 wt.% and a zinc content of 30 wt.% to 39 wt.%, • that the monofilaments each have a linear density of 92 g / 100 m to 105 g / 100 m, • that the monofilaments have a tensile density Td of 34 MPa / (g / 100m) to 39 MPa / (g / 100m), where the tensile density Td is defined as the quotient of a tensile strength and the linear density of the respective reinforcing material, • that the reinforcement layer has a surface strength AS of 109 Nmm 2 up to 166 Nmm 2 exhibits, wherein the surface strength AS is given as the product of a breaking force and a diameter d of a monofilament of the reinforcement layer as well as a distance x between the monofilament and an adjacent monofilament of the reinforcement layer, • that the rubber matenal has an elongation at break of 300% to 450%.

2. Vehicle pneumatic tire according to claim 1, characterized in that the Monofilaments have a compression modulus of 138 GPa to 155 GPa and / or exhibit a compression set of 0.95% to 1.05% and / or a compression stress of 1400 MPa to 1500 MPa. Vehicle pneumatic tires according to one or more of the preceding claims, characterized in that the monofilaments each have an out-of-plane flexural stiffness of 270 Nmm². 2 up to 340 Nmm 2Vehicle pneumatic tires according to one or more of the preceding claims, characterized in that the monofilaments each have a tensile strength of 3500 MPa to 3700 MPa, preferably that a force of 285 N to 325 N is required for an elongation of 1%. Vehicle pneumatic tires according to one or more of the preceding claims, characterized in that the reinforcing layer has a steel content of 47 wt.% to 63.5 wt.%, preferably 48.9 wt.% to 62.3 wt.%, particularly preferably 52 wt.% to 58 wt.%.-% and that the reinforcing layer has a spacing factor S of 2.00 to 2.67, preferably of 2.05 to 2.57, particularly preferably of 2.10 to 2.50, wherein S = 1 + ((y + y' + x) / (2xd)), where y is a thickness of the reinforcing layer on a first side of a monofilament of the reinforcing layer, y' is a thickness of the reinforcing layer on an opposite second side of the monofilament, x is a distance between the monofilament and an adjacent monofilament of the reinforcing layer, and d is a diameter of the monofilament. Vehicle pneumatic tires according to one or more of the preceding claims, characterized in that the monofilaments are free of twist about their axis. Vehicle pneumatic tires according to one or more of the preceding claims, characterized in that the monofilaments have a twist angle of at most 10°, preferably at most 1°. Vehicle pneumatic tires according to one or more of the preceding claims, characterized in that the rubber material has a tensile strength of 15 N / mm². 2 up to 22 N / mm 2A vehicle pneumatic tire according to one or more of the preceding claims, characterized in that the rubber material has a Shore hardness of 77 to 81 (Shore A). A vehicle pneumatic tire according to one or more of the preceding claims, characterized in that the rubber material has a rebound elasticity of 38 to 45. A vehicle pneumatic tire according to one or more of the preceding claims, characterized in that the vehicle pneumatic tire, in particular of radial design, has a belt and that the reinforcing layer is a reinforcing layer of the belt, preferably that the belt has two such reinforcing layers whose reinforcing elements intersect at an angle of 18° to 45°.Vehicle pneumatic tire according to one or more of the preceding claims, characterized in that the vehicle pneumatic tire, in particular of radial design, has a carcass and that the reinforcing layer is a reinforcing layer of the carcass.

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